i now have pics of the power supply and socket
this is the plug from power supply to PC
this is where it plugs into the PC
and this is the power supply brick
i looked into using the citrix p2140 but i do not think the plugs would match, people have used it for the sx270 which has 6 outputs from the powersupply, when mine has 8 outputs.
this is getting me confused.
also i just thought of an idea, why not use a UPS to power the computer, just remove the UPS battery and connect the car's battery to it, it works exactly the same. regulated too.